FIELD OF THE INVENTION
The present invention relates to a device for adjusting one of the bearing blocks of a roller in a roller group for supporting and moving an endless moved web, such as the traveling screen or conveyor belt in a papermaking plant. The bearing block is disposed on a slide which is adjustable along at least one guide rail and which can be adjusted relative to a carrying structure in the conveying direction of the roller section by an actuating device. As a result, the angular position of the roller mounted in the bearing block is variable relative to the conveying direction of the roller section.
In plants in which an endless moved web is guided via a multiplicity of mutually adjacent rollers, such as, for example, in a papermaking plant using a traveling screen which is guided via a multiplicity of successive rollers, there is the requirement that the direction of movement of the band coincides exactly with the conveying direction of the roller section. By contrast, insofar as the direction of movement of the band deviates from the conveying direction of the roller section due to irregularities in the band or rollers or for other reasons, with the result that the direction of movement of the band forms an acute angle with the conveying direction of the roller section, this not only leads to inadmissible loads on the band, but, moreover, the band may creep laterally out of the roller section, thus causing operating faults.
It has been known in the art, for monitoring the direction of movement of the band which is guided via a roller section, to provide a measuring means, by which inadmissible deviations of the direction of movement of the band from the conveying direction of the roller section are detected. In response to the monitoring it is possible to take corrective mn in order to correct the direction of movement of the band. Correction is possible, in this case, due to the fact that the angular position of one or a plurality of the rollers of the roller section is varied slightly.
The orientation of a roller of the roller section can be varied by adjusting one of the two bearing blocks in the conveying direction of the roller section. For that purpose, a piston/cylinder assembly is arranged below the bearing block. The cylinder is thereby rigidly fastened in the structure of the plant below the bearing block and, furthermore, the bearing block is carried by the piston which can be adjusted in the conveying direction of the roller section within the cylinder. By the displacement of the piston, the angular orientation of the roller carried by the bearing block relative to the conveying direction of the roller section can be adjusted, with the result that the direction of movement of the band can be influenced.
The prior art system is disadvantageous, however, in that the forces absorbed by the bearing block are transmitted via the piston to the cylinder, thus causing a high load to be exerted on the seals between the piston and the cylinder. Moreover, the prior art device is disadvantageous in that the piston/cylinder assembly is located below the associated bearing block. Access to the piston/cylinder assembly for maintenance or repair is difficult.
European published patent application EP 733 736 A2 discloses a device that avoids this disadvantage by providing, on the slide, a carriage which is provided with running rollers and which can be moved relative to the carrying structure by a further actuator. Even though that prior art device is advantageous relative to the previously known art, it nevertheless has the disadvantage that it must be dismantled completely if the running rollers or other components are damaged or broken, so that the damaged or inoperative components can be removed and replaced with new components.